Film forming method and apparatus

ABSTRACT

A film forming method, for depositing a thin film on a surface of a substrate mounted on a mounting table disposed in a vacuum processing chamber, includes an adsorption process for adsorbing a film forming material on the substrate by introducing a source gas into the processing chamber; and a reaction process for carrying out a film forming reaction, after the adsorption process, by introducing an energy transfer gas into the processing chamber and supplying thermal energy to the film forming material adsorbed on the substrate. By repeating the above process, the thin film is formed on the substrate in a layer-by-layer manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of pending U.S.application Ser. No. 11/608,504, filed on Dec. 8, 2006, which claimspriority to Japan Patent Application No. 2005-335152, filed on Dec. 8,2005. The entire contents of each of the above applications areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a film forming method and apparatus;and, more particularly, to a film forming method for forming a desiredthin film on a surface of a substrate by using an ALD (atomic layerdeposition) method and a film forming apparatus therefor.

BACKGROUND OF THE INVENTION

As for a representative film forming method for forming a solid thinfilm on a surface of a substrate such as a semiconductor wafer or thelike, there is known a CVD (chemical vapor deposition) method. When afilm is formed by using the CVD method, a source needs to be activatedby applying energy to a source gas. Accordingly, there has been employeda CVD method for supplying thermal energy to a source gas through asubstrate heated by a heater provided at a mounting table for mountingthereon the substrate or a plasma CVD method for supplying energy of aplasma generated in a space above a substrate by introducing a sourcegas into the atmosphere thereof.

A film forming apparatus for manufacturing an advanced very large scaleintegrated circuit needs to have a performance (a step coverageperformance) of forming a high-quality thin film of a uniform thicknessalong surfaces of holes/grooves previously formed on a surface of asemiconductor wafer with a diameter/width of tens of nanometers.

In order to obtain a high step coverage performance, a surface reactionneeds to take place by activating a source gas on an uppermost surfaceof a substrate, not by activating it in a gas phase space above thesubstrate. However, in the CVD method for forming a film by continuouslysupplying a source gas, a reactant gas and energy, certain source gasesmay cause a gas phase reaction by an excessive activation thereof in agas phase. Since the gas phase reaction greatly deteriorates the stepcoverage performance, there arises a need to suppress the gas phasereaction and facilitate the surface reaction in order to maintain thehigh step coverage performance.

As for another method for forming a thin film on a surface of asubstrate, there is known an atomic layer deposition (ALD) method. Withthe ALD method, a thin film having high step coverage can be formed on asubstrate disposed inside a vacuum chamber by repetitively performing afilm forming process and a purge process. In the ALD film formingprocess, a reaction is carried out by supplying energy to amonomolecular or a multimolecular adsorption layer adsorbed on asurface, the adsorption layer being formed of molecules of a sourcecompound. In the purge process, the atmosphere inside the vacuum chamberis substituted.

The ALD method for forming a film while suppressing a gas phase reactionwas suggested in 1977 by Suntola et al. (see U.S. Pat. No. 4,058,430).The method is performed by alternately supplying a source gas and areactant gas to a substrate at different timings, as shown in FIG. 24,and then removing a residual source gas and a by-product gas of aprevious cycle remaining in a gas phase with a non-reactive purge gasbefore supplying the source gas and the reactant gas again. The gasphase reaction can be suppressed by repeating those cycles. Further, thehigh step coverage performance can be maintained by restricting thereaction to take place at the uppermost surface of the substrate. Thereare plenty of reports on the ALD method (see, e.g., R. L. Puurunen,“Surface chemistry of atomic layer deposition: A case study for thetriethylaluminum/waterprocess”, Journal of Applied Physics, APPLIEDPHYSICS REVIEW, vol. 97, p 121301 (2005)).

In an initial ALD method, although the source gas and the reactant gasare separately provided as shown in FIG. 24, the energy (heat) isconstantly supplied. This is because the initial ALD method supplies thethermal energy to a surface of a substrate via the substrate by heatingthe entire substrate as in the thermal CVD method and, therefore, a timeresponsiveness in controlling an on/off of energy supply becomes poor(see, e.g., U.S. Pat. No. 4,389,973). Such an ALD method is referred toas “thermal ALD method”. In this method, since the energy is constantlysupplied during a source gas supply process, parts of the source gas mayever cause an self-pyrolysis reaction in a gas phase by receiving thethermal energy transferred in the gas phase from the substrate, whichleads to a deterioration of the step coverage performance.

Moreover, since the entire substrate is heated constantly during theprocessing, a solid layer that has been formed by a previous process maybe deteriorated by the heat.

To solve those drawbacks, Sherman et al. has suggested an ALD method forsupplying energy by radicals generated by an RF power supply (see U.S.Pat. No. 5,916,365). Further, Chiang et al. has suggested a method forsupplying energy by radicals and ions generated from a plasma (see U.S.Pat. No. 6,416,822). In these methods, the energy is supplied not byheat but by chemically active species (radicals, ions or combinationthereof) generated from the RF power supply, so that an ON/OFF of energysupply can be controlled with fine time-responsiveness. Such an ALDmethod is referred to as “a plasma-assisted ALD method”.

In the plasma-assisted ALD method, a source gas supplying process and anenergy supplying process can be carried out at different timings.Therefore, it is possible to prevent a self-pyrolysis reaction of thesource gas from taking place during the source gas supplying process,the self-pyrolysis reaction being caused by the continuous supply ofthermal energy. Further, since such a method is not a method forsupplying energy through a substrate being continuously heated, it ispossible to avoid the problem of deteriorating the previously formedsolid layer with the heat.

However, the method using as an energy source radicals or ions generatedfrom a plasma has new problems to be described as follows.

Firstly, the excessively high energy of the active species (radicals,ions and electrons) generated from a plasma inflicts a serious physicaldamage or causes a chemical deterioration on a base layer of a substratewhere a film will be formed (see, e.g., A. Grill et al, “Hydrogen plasmaeffects on ultra low-k porous SiCOH dielectric”, Journal of AppliedPhysics, vol. 98, p 074502 (2005)).

Secondly, the active species also collide against not only the substratebut also an inner surface of an apparatus in contact with the plasma,thereby causing a physical sputtering, which in turn result in impurityincorporation into the surface of the substrate.

Thirdly, since the energy is also supplied by the active species to sidechain groups contained in the source gas that are desirably to beremoved by the reaction, the side chain groups may be incorporated asundesired impurities into the film.

Fourthly, a potential gradient generated inside the apparatuselectrically may destroy fine integrated circuits formed on thesubstrate.

Fifthly, high energy ultraviolet rays generated from the plasma maydeteriorate the base layer of the substrate.

As long as the energy is supplied by using the plasma, theaforementioned problems may be only partially, but not completely,avoided.

In order to avoid those problems generated in supplying energy by theplasma, Chiang et al. has suggested a method for supplying energy bylight (see, U.S. Pat. No. 6,878,402). In case the energy is supplied byirradiating light on a surface of a substrate, a window for transmittingthe light needs to be provided above the substrate. Since, however, asurface of the window becomes dirty during a film forming process, thelight is reflected or absorbed and, thus, an intensity of the lightreaching the substrate decreases. Moreover, in case the surface of aprocessing target substrate is made of a metal, the light is reflectedon the surface of the substrate, which hinders the energy supply for thereaction.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a filmforming method capable of forming a high-quality thin film having highstep coverage on a surface of a substrate without deteriorating a thinfilm previously formed on the substrate with heat or inflicting plasmadamages thereon.

The present inventors have achieved the present invention by conceivingan energy supply method based on the ALD method and finding solutions tothe aforementioned problems.

In accordance with a first aspect of the present invention, there isprovided a film forming method for depositing thin films on a surface ofa substrate mounted on a mounting table arranged in a vacuum evacuableprocessing chamber, the method comprising the steps of: an adsorptionprocess for adsorbing a film forming material on the substrate byintroducing a source gas into the processing chamber; and a reactionprocess for carrying out a film forming reaction, after the adsorptionprocess, by introducing an energy transfer gas into the processingchamber and supplying thermal energy to the film forming materialadsorbed on the substrate.

In view of the first aspect, it is preferable to further include a purgeprocess for introducing a purge gas into the processing chamber.Preferably, the adsorption process and the reaction process arealternately performed, and the purge process is performed therebetween.Moreover, it is preferable to further include a pressure increasingprocess for increasing a pressure inside the processing chamber beforethe reaction process. In such a case, it is preferable that a pressuredecreasing process for decreasing an inner pressure of the processingchamber is provided upon or after the reaction process is completed. Inthe reaction process, it is preferable to introduce a reactant gaschemically participating in the film forming reaction in addition to theenergy transfer gas. Further, it is preferable that the reactant gas isone of a reduction gas, a carbonization gas, a nitrification gas and anoxidizing gas.

Further, it is preferable that the energy transfer gas is selected amonga reduction gas, a carbonization gas, a nitrification gas and anoxidizing gas.

Preferably, the source gas is introduced and exhausted such that a gasflow is formed in a direction parallel to the surface of the substratemounted on the mounting table. Furthermore, preferably, the source gasis introduced and exhausted such that a gas flow is formed in adirection of colliding against the surface of the substrate mounted onthe mounting table. Preferably, the energy transfer gas is injectedtoward the surface of the substrate mounted on the mounting table, thesurface having the film forming material adsorbed thereon.

Preferably, the adsorption process is performed while controlling atemperature of the substrate mounted on the mounting table to a level atwhich the film forming material is absorbable.

Preferably, the film forming material contains at least one metalelement selected from a group consisting of Al, Si, Ti, Cr, Mn, Fe, Co,Ni, Cu, Zn, Ge, Zr, Mo, Ru, Rh, Pd, Ag, Ba, Hf, Ta, W, Re, Ir and Pt.Further, it is preferable that the thin films are deposited on thesubstrate by repeating a plurality of cycles of performing a filmforming reaction with a film forming material of a monomolecular or amultimolecular adsorption layer through an atomic layer depositionmethod.

In accordance with a second aspect of the present invention, there isprovided a computer-executable program for controlling the processingchamber such that the film forming method of the first aspect of thepresent invention is performed.

In accordance with a third aspect of the present invention, there isprovided a computer readable storage medium for storing therein acomputer-executable program, wherein the control program controls theprocessing chamber such that the film forming method of the first aspectof the present invention is performed.

In accordance with a fourth aspect of the present invention, there isprovided a film forming apparatus including: a processing chamberaccommodating therein a substrate, for performing a film formingprocess; a mounting table for mounting thereon the substrate in theprocessing chamber; a source gas inlet for introducing a source gas intothe processing chamber; an energy transfer gas inlet for injecting anenergy transfer gas toward a surface of the substrate mounted on themounting table in the processing chamber; a gas exhaust unit for vacuumexhausting an inside of the processing chamber; and a controller forcontrolling the film forming method described in any one of claims 1 to14 to be performed.

In accordance with a fifth aspect of the present invention, there isprovided a film forming apparatus including: a processing chamberaccommodating therein a substrate, for performing a film formingprocess; a mounting table for mounting thereon the substrate in theprocessing chamber; a source gas inlet for introducing a source gas intothe processing chamber; an energy transfer gas inlet for injecting anenergy transfer gas toward a surface of the substrate mounted on themounting table in the processing chamber; and a gas discharge portconnected with a gas exhaust unit for vacuum exhausting an inside of theprocessing chamber, wherein the source gas inlet and the gas dischargeport are provided such that the introduced source gas flows in adirection parallel to a surface of the substrate mounted on the mountingtable before being exhausted.

In accordance with a sixth aspect of the present invention, there isprovided a film forming apparatus including: a processing chamberaccommodating therein a substrate, for performing a film formingprocess; a mounting table for mounting thereon the substrate in theprocessing chamber; a source gas inlet for introducing a source gas intothe processing chamber; an energy transfer gas inlet for injecting anenergy transfer gas toward a surface of the substrate mounted on themounting table in the processing chamber; and a gas discharge portconnected with a gas exhaust unit for vacuum exhausting an inside of theprocessing chamber by a depressurization, wherein the source gas inletand the gas discharge port are provided such that the source gas isintroduced and exhausted in a direction of colliding against the surfaceof the substrate mounted on the mounting table.

In accordance with the film forming apparatus of the fifth and the sixthaspect of the present invention, it is preferable that the mountingtable includes a temperature control unit for controlling a temperatureof the substrate mounted thereon to a level at which a source materialis absorbable on the substrate.

In accordance with the film forming method of the present invention, theadsorption process for adsorbing a film forming material on a substrateby introducing a source gas into a processing chamber is performed at adifferent timing from the reaction process for carrying out a filmforming reaction by introducing an energy transfer gas into theprocessing chamber and supplying thermal energy to the film formingmaterial adsorbed on the substrate. Accordingly, the whole substratedoes not need to be heated for a long period of time. Further, since thethermal energy is supplied by using the energy transfer gas, a surfaceof the substrate is mainly heated. Therefore, it is possible to avoiddrawbacks of a conventional thermal ALD method, such as a deteriorationof a solid layer due to a heat, a deterioration of step coverage due toa self-pyrolysis of a gaseous source gas and the like. Moreover, it isalso possible to avoid drawbacks of a plasma-assisted ALD method, suchas a damage inflicted on a substrate due to a plasma, a deterioration ofa film quality due to a sputtering or an excessive activation of asource gas, and the like. Furthermore, the present invention provides ahigh energy efficiency of the entire process.

Moreover, in accordance with the film forming apparatus of the presentinvention, a stage heater for maintaining a high temperature of asubstrate, a plasma generating device and the like are not required and,also, a high-quality thin film can be formed with a simpleconfiguration.

While the invention has been shown and described with respect to theembodiments, it will be understood by those skilled in the art thatvarious changes and modification may be made without departing from thescope of the invention as defined in the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention willbecome apparent from the following description of embodiments, given inconjunction with the accompanying drawings, in which:

FIG. 1 is a cross sectional view showing a schematic configuration of afilm forming apparatus in accordance with a first embodiment of thepresent invention;

FIGS. 2A and 2B describe arrangements of gas injection openings formedon a bottom surface of a shower head, wherein FIG. 2A provides anexample of a concentric arrangement, and FIG. 2B depicts an example of agrid pattern arrangement;

FIG. 3 illustrates a schematic configuration of a heater provided aroundthe injection openings;

FIG. 4 presents a flowchart for explaining exemplary processes of a filmforming method of the present invention;

FIG. 5 represents a flowchart for explaining another exemplary processesof the film forming method of the present invention;

FIG. 6 depicts a timing chart of the exemplary processes of FIG. 5;

FIG. 7 provides a flowchart for explaining still another exemplaryprocesses of the film forming method of the present invention;

FIG. 8 describes a timing chart of the exemplary processes of FIG. 7;

FIG. 9 is a flowchart for explaining still another exemplary processesof the film forming method of the present invention;

FIG. 10 shows a timing chart of the exemplary processes of FIG. 9;

FIGS. 11A to 11J illustrate schematic views for explaining a principleof the film forming method of the present invention;

FIG. 12 presents a schematic configuration of a film forming apparatusin accordance with a second embodiment of the present invention;

FIG. 13 represents a schematic configuration of a film forming apparatusin accordance with a third embodiment of the present invention;

FIG. 14 describes a timing chart of a film formation of a first example;

FIG. 15 illustrates a timing chart of a film formation of a secondexample;

FIG. 16 provides a timing chart of a film formation of a third example;

FIG. 17 shows a timing chart of a film formation of a fifth example;

FIG. 18 offers a timing chart of a film formation of a sixth example;

FIG. 19 depicts a timing chart of a film formation of a seventh example;

FIG. 20 presents a timing chart of a film formation of a ninth example;

FIG. 21 represents a timing chart of a film formation of a tenthexample;

FIG. 22 illustrates a schematic configuration of a shower head having acylindrical heater;

FIG. 23 shows a schematic configuration of the cylindrical heater; and

FIG. 24 offers a timing chart of a conventional thermal ALD.

DETAILED DESCRIPTION OF THE EMBODIMENT

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1 is a cross sectional view schematically showing an exemplary filmforming apparatus suitable for performing a film forming method of thepresent invention. Such a film forming apparatus 100 has a substantiallycylindrical airtight chamber 1. A circular opening 2 is formed at acentral portion of a bottom wall 1 a of the chamber 1. Further, arrangedinside the chamber 1 is a mounting table 3 made of ceramic such as AlNor the like, for horizontally supporting a wafer W (a semiconductorsubstrate). An insulating unit 4 is provided between the mounting table3 and the bottom wall 1 a and airtightly contacted with the bottom wall1 a of the chamber 1.

A gas exhaust port 5 is formed on a sidewall 1 b of the chamber 1 andconnected with a gas exhaust unit 7 via a gas exhaust line 6 connectedtherewith, the gas exhaust unit 7 having a high speed vacuum pump.Moreover, a conductance variable valve 6 a is provided in the gasexhaust line 6 to control a gas exhaust amount from the chamber 1. Asfor the conductance variable valve 6 a, there can be used, e.g., abutterfly valve or the like. By operating the gas exhaust unit 7, a gasinside the chamber 1 is exhausted and, further, an inside of the chamber1 can be depressurized to a predetermined vacuum level at a high speedvia the gas exhaust line 6.

A shower head 10 is provided on a ceiling wall 1 c of the chamber 1.Disposed on an upper wall of the shower head 10 is a gas inlet port 12for introducing a gas into the shower head 10. Connected to the gasinlet port 12 is a line 13 for supplying an energy transfer gas such asHe, Ar, Kr, Xe, H₂, N₂, CO₂, CH₄ or the like. The other end portion ofthe line 13 connected with the gas inlet port 12 is branched into two.One is connected with an energy transfer gas supply source 23 a via amass flow controller 21 a and valves 22 a provided in its forward andbackward direction, and the other is connected with a reactant gassupply source 23 b via a mass flow controller 21 b and valves 22 bprovided in its forward and backward direction.

A diffusion space 14 is formed inside the shower head 10. The gasintroduced from the gas inlet port 12 is diffused in the diffusion space14. Formed at a lower portion of the shower head 10 are a plurality ofgas injection openings 11 for discharging the energy transfer gas andthe reactant gas toward the mounting table 3. The gas injection openings11 may be arranged in any pattern. For example, they can be formed in aconcentric pattern as shown in FIG. 2A or in a grid pattern asillustrated in FIG. 2B. Further, a diameter or the number of the gasinjection openings 11 can be appropriately determined depending on filmtypes.

Provided near each of the gas injection openings 11 of the shower head10 is a heater 15 serving as heating units for heating the energytransfer gas inside the shower head 10. Moreover, insulating units 16are provided around the heaters 15 to insulate the heaters 15, theinsulating units 16 being made of a material having a low thermalconductivity, such as heat resistant synthetic resin, quartz, ceramic orthe like. FIG. 3 shows an exemplary configuration of a heater 15. Theheater 15 includes a cylindrical ceramic member 15 a formed to surroundthe gas injection openings 11 and a resistance (heating wire) 201embedded in a coil shape in the ceramic member 15 a. By supplying powerfrom a heater power supply (not shown) to the resistance 201 via a leadline 202, the energy transfer gas flowing through inside the resistance(heating wire) 201 can be instantly and effectively heated.

A gas inlet port 17 is provided at the opposite side of the gas exhaustports 5 provided on the sidewall 1 b of the chamber 1 and connected witha gas exhaust line 18 for supplying a source gas and a purge gas to thechamber 1. The other end portion of the line 18 is branched into two.One is connected with connected with a source gas supply source 26 via amass flow controller 24 a and valves 25 a provided in its forward andbackward direction, and the other is connected with a purge gas supplysource 27 via a mass flow controller 24 b and valves 25 b provided inits forward and backward direction.

A film forming source gas supply source 26 is configured to supply asource gas. The source gas contains a metal element in a part of amolecular structure and supplies the metal element as a main constituentof a thin film produced by a reaction. As for the metal element, therecan be employed a third periodic element in the periodic table, such asAl, Si or the like, fourth periodic element such as Ti, Cr, Mn, Fe, Co,Ni, Cu, Zn, Ge or the like, fifth periodic element such as Zr, Mo, Ru,Rh, Pd, Ag or the like or sixth periodic element such as Ba, Hf, Ta, W,Re, Ir, Pt and the like.

As for a metal compound forming a source gas, there can be used one ofthe following exemplary metal compounds:

-   -   Al: Al(CH₃)₃    -   Ti: Ti[N(CH₃)₂]₄; tetrakis(dimethylamino)titanium (TDMAT)    -   Cr: Cr(CO)₆    -   Mn: Mn₂(CO)₁₀    -   Fe: Fe(CO)₅, Fe₂(CO)₉, Fe₃(CO)₁₂    -   Co: Co₂(CO)₈    -   Ni: Ni(CO)₄, Ni(acac)₂; acac representing Acetylacetone        (2,4-pentadion)    -   Cu: (Hfac)CuTMVS; Hfac representing hexafluoroacetylacetone, and        TMVS representing trimethylvinylsilane    -   Zn: Zn(CH₃)₂    -   Ge: Ge(OCH₃)₄    -   Zr: Zr(O-t-C₄H₉)₄    -   Mo: Mo(CO)₆    -   Ru: Ru₃(CO)₁₂, Ru(EtCp)₂; EtCp representing ethyl        cyclopantadiene    -   Rh: Rh₄(CO)₁₂    -   Pd: Pd(OAc)₂; OAc representing acetate    -   Ag: Ag[O₂C—C(CH₃)₃]; 2,2-dimethylpropionate silver (I)    -   Ba: Ba(O₂C₁₁H₁₉)₂; Bis(dipivaloymethanato)barium    -   Hf: Hf (C₁₁H₁₉O₂) 4    -   Ta: Ta(N-t-C₅H₁₁) [N(CH₃)₂]₃; Tertiaryamylimidotris        (dimethylamido) tantalum    -   W: W(CO)₆    -   Re: Re₂(CO)₁₀    -   Ir: Ir(C₅H₄C₂H₅) (C₈H₁₂);        ethylcyclopentadienyl(1,5-cyclooctadiene)iridium    -   Pt: Pt(C₅H₄C₂H₅) (CH₃)₃;        ethylcyclopentadienyl(trimethyl)platinum

If necessary, the film forming source gas supply source 26 may beprovided with a plurality of source gas supply sources (not shown).Further, in order to introduce the source gas into the chamber, theremay be provided, e.g., a heating equipment for sublimating a solid filmforming material, a vaporizer for vaporizing a liquid film formingmaterial and the like in addition to a carrier gas supply source forsupplying a carrier gas such as Ar or the like (all not shown).

The purge gas supply source 27 is configured to supply a purge gas. Thepurge gas is used to purge a source gas remaining in a gas phase,by-products generated in the gas phase by a reaction and an energytransfer gas containing a large amount of thermal energy. As for thepurge gas, there can be employed H₂ gas or a non-reactive gas such as Argas, He gas, N₂ gas or the like. By introducing the purge gas, theresidual source gas in the line 18 can be exhausted. Further, theby-products can be removed by substituting the atmosphere inside thechamber 1. Furthermore, the wafer W can be cooled.

A clamp ring 28 for fixing the wafer W is provided at an outerperipheral portion of the mounting table 3. The clamp ring 28 moves upand down by an elevating mechanism 29 and fixedly presses downward thewafer W mounted on the mounting table 3. Although a thickness of theclamp ring 28 is exaggerated in FIG. 1, the actual thickness is set suchthat a contact between the source gas and a surface of the wafer W isnot interfered. Further, the mounting table 3 is provided with threewafer supporting pins (not shown) capable of protruding and retractingrelative to a surface of the mounting table 3 so that the wafer W can besupportively lifted up and down.

A temperature control medium chamber 30 is formed inside the mountingtable 3 and configured to control a temperature of the mounting table 3by introducing thereinto a temperature control medium of a predeterminedtemperature, e.g., water or Galden (trademark) as a fluorine-basednon-reactive liquid, through an introduction path 31 a and thendischarging it through a discharge path 31 b.

A gas channel 32 is formed inside the mounting table 3 from a lowerportion of the mounting table 3 to a top surface of the mounting table3, i.e., a mounting surface of the wafer W. Also, the gas channel 32 isbranched into a plurality of gas injection openings 32 a near themounting surface to thereby supply a heat transfer gas, e.g., He gas orthe like, to a backside of the wafer W in multiple places at apredetermined pressure. In this way, the temperature of the mountingtable 3 is transferred to the wafer W and, accordingly, the temperaturethereof is controlled.

The temperature control medium chamber 30 for circulating thetemperature control medium and the gas channel 32 for supplying the heattransfer gas to the backside of the wafer W cooperatively serve as atemperature control unit for controlling a temperature of the wafer W.

Provided on the sidewall 1 b of the chamber 1 are a loading/unloadingport (not shown) for loading/unloading the wafer W to/from a transferchamber (not shown) disposed adjacent to the film forming apparatus 100and a gate valve (not shown) for opening/closing the loading/unloadingport.

Each component of the film forming apparatus 100 is connected with aprocess controller 50 having a CPU and controlled by the processcontroller 50. The process controller 50 is connected with a userinterface 51 having a keyboard, a display and the like. A processoperator uses the keyboard when inputting commands for managing theplasma processing apparatus 100, and the display is used to display theoperation status of the film forming apparatus 100.

Also, the process controller 50 is connected with a storage unit 52 forstoring therein recipes including control programs (software) forimplementing various processes in the film forming apparatus 100 underthe control of the process controller 50, processing condition data andthe like.

If necessary, the process controller 50 executes a recipe read from thestorage unit 52 in response to instructions from the user interface 51,thereby implementing a desired process in the film forming apparatus 100under the control of the process controller 50. For example, the processcontroller 50 controls each mass flow controller, each valve and the gasexhaust unit 7. Accordingly, the source gas, the carrier gas, the purgegas and the like are controlled to be supplied at required flow ratesthereof, or the supply thereof is stopped. Furthermore, the recipes suchas the control programs, the processing condition data and the like canbe read from a computer-readable storage medium, e.g., a CD-ROM, a harddisk, a flexible disk, a flash memory or the like, or transmittedon-line from another device via, e.g., a dedicated line when necessary.

Hereinafter, a sequence of forming a desired film by using the filmforming apparatus 100 will be described with reference to FIG. 4. Firstof all, while a gate valve (not shown) is opened, the wafer W is loadedinto the chamber 1 via the loading/unloading port and then mounted onthe mounting table 3 (step S11). Next, a temperature control medium of apredetermined temperature is introduced into the temperature controlmedium chamber 30 and, also, a heat transfer gas such as He gas or thelike is introduced into the gas channel 32. By injecting the heattransfer medium gas from the multiple injection openings 32 a to thebackside of the wafer W, a temperature of the wafer W is controlleduntil it reaches a level enabling the film forming material to be easilyadsorbed on a surface of the wafer W (step S12). Although thetemperature can vary depending on types of film forming material, it canbe controlled between −20° C. and 100° C., for example.

The inside of the chamber 1 is exhausted by a vacuum pump of the gasexhaust unit 7. Next, while the valves 25 a are opened, a source gas issupplied from the film forming source gas supply source 26 to thechamber 1 via the gas inlet port 17 at a flow rate controlled by themass flow controller 24 a. By performing the exhaust with an operationof the gas exhaust unit 7, the source gas flows from the gas inlet port17 toward the gas exhaust port 5 in a direction parallel to the surfaceof the wafer W mounted on the mounting table 3, as indicated by whitearrows of FIG. 1. Due to the flow of the source gas, the film formingmaterial is physically or chemically adsorbed on the surface of thewafer W (step S13). Although an inner pressure of the chamber 1 duringthe adsorption process can vary depending on types of source materials,it is preferably controlled between 10 Pa and 1000 Pa, for example.

Thereafter, while the valves 25 a are closed and the valves 25 b areopened, the purge gas is supplied from the purge gas supply source 27 tothe chamber 1 via the gas inlet port 17 at a flow rate controlled by themass flow controller 24 b. By performing the exhaust with an operationof the gas exhaust unit 7, the atmosphere inside the chamber 1 issubstituted by the purge gas. Consequently, a residual gaseous sourcegas is removed (step S14).

Before an energy transfer gas is introduced into the chamber, an innerpressure of the chamber 1 is increased in a step S15. By increasing thepressure, when the energy transfer gas is introduced into the chamber ina next step 16, a temperature can be prevented from decreasing due to anexpansion of the energy transfer gas and it is possible to suppress adesorption and a diffusion of the source gas adsorbed on the surface ofthe wafer W.

The pressure can be increased, under the control of the processcontroller 50, by constantly introducing the purge gas and adjusting anexhaust conductance with the use of the conductance variable valve 6 aarranged on the gas exhaust line 6 between the gas exhaust port 5 andthe gas exhaust unit 7. At this time, the gas exhaust unit 7 and theconductance variable valve 6 a cooperatively serve as a pressure controlunit. In the step S15 of increasing the pressure, it is preferable thatthe inner pressure of the chamber 1 is set to be between 500 Pa and 5000Pa, for example.

It is preferable to carry out, after purging a certain amount of sourcegas by the purging step S14, the step S15 of increasing the innerpressure of the chamber 1 by using the purge gas and adjusting anexhaust amount through the use of the pressure control unit. However,the steps S14 and S15 can be simultaneously performed to reduce aprocessing time. In other words, upon the purge gas is introduced intothe chamber 1, the pressure can be increased by controlling the exhaustamount with the use of pressure control unit.

Next, while the valves 25 b are closed and the valves 22 a are opened,the energy transfer gas is introduced from the energy transfer gassupply source 23 a into the diffusion space 14 of the shower head 10 viathe gas inlet port 12 at a flow rate controlled by the mass flowcontroller 21 a. The energy transfer gas facilitates a film formingreaction by conveying thermal energy transferred thereto from theheating unit such as the heaters 15 or the like to the source gasadsorbed on the surface of the wafer W (substrate).

As indicated by black arrows of FIG. 1, the energy transfer gasintroduced into the diffusion space 14 is substantially verticallyinjected to the surface of the wafer W through the multiple gasinjection openings 11 disposed opposite to the wafer W in the lowerportion of the shower head 10. At this time, the energy transfer gas isheated to a predetermined high temperature by the heaters 15 serving asthe heating unit and thus collides against the surface of the wafer Wwith the sufficient thermal energy.

When starting introducing the energy transfer gas into the diffusionarea 14 of the shower head 10, it is preferable to increase an inputpower to the heaters 15 rapidly so that the heat can be effectivelyconveyed to the energy transfer gas. Each of the heaters 15 iscontrolled by the process controller 50.

Although a heating temperature of the energy transfer gas may varydepending on target film types, it is preferably within the range from300 to 1000° C., for example. Further, it is preferable to maintain theinner pressure of the chamber at the level obtained in the pressureincreasing process (step S15) in view of effectively performing the filmforming reaction.

Since the film forming material in the source gas is adsorbed on thesurface of the wafer W as described above, the thermal energy requiredfor the film forming reaction can be effectively supplied by injectingthe high-temperature energy transfer gas thereto. Consequently, the filmforming reaction is carried out on the surface of the wafer W, therebyforming a thin film corresponding to a monomolecular or a multimolecularadsorption layer of a source gas adsorbed on the surface of the wafer W(step S16). Moreover, the energy transfer gas can be heated in advanceto a predetermined temperature by an external heating unit before beingintroduced into the shower head 10. At this time, the heaters 15provided at the lower portion of the shower head 10 can serve asauxiliary heating units for final temperature regulation of the energytransfer gas.

When two or more types of gases are used as source gas to supply pluralsepecies of metal elements, each of the gases may undergo the adsorptionprocess of the step S13 and the purge process of the step S14. Inaddition to the energy transfer gas, a reactant gas chemicallyparticipating in the film forming reaction may be introduced in thereaction process of the step S16. That is, by opening the valves 22 b,the reactant gas is introduced from the reactant gas supply source 23 binto the diffusion space 14 of the shower head 10 at a flow ratecontrolled by the mass flow controller 21 b and then injected into thechamber 1.

The reactant gas contains no metal elements in its molecular structureand is used to oxidize, reduce, carbonize and nitrify metal elements ofa film forming material by reacting with the film forming material. Asfor the reactant gas, there can be used, e.g., an oxidizing gas (O₂, O₃,H₂O or the like), a reduction gas (H₂, organic acid such as HCOOH,CH₃COOH or the like, or alcohol such as CH₃OH, C₂H₅OH or the like), acarbonization gas (CH₄, C₂H₆, C₂H₄, C₂H₂ or the like), a nitrificationgas (NH₃, NH₂NH₂, N₂ or the like) or the like. The “reactant gas” of thepresent invention includes the aforementioned H₂O, organic acid,alcohol, NH₂NH₂ or the like, which is a liquid in a normal temperatureand pressure condition. The elements forming the reactant gas may beincorporated into the film as a result of the reaction or may serve onlyto facilitate the reaction without being incorporated into the film.Whether to employ the reactant gas or not is determined depending ontypes of film forming materials and those of target films.

Further, by heating the reactant gas, the reactant gas can be used asthe energy transfer gas.

After the reaction process of the step S16 is completed, it ispreferable to stop the introduction of the energy transfer gas byclosing the valves 22 a and perform a pressure decreasing process fordecreasing the inner pressure of the chamber 1 (step S17). By reducingthe inner pressure of the chamber 1 after the reaction process, theenergy transfer gas is exhausted and the energy supply to the surface ofthe wafer W is stopped in a short period of time. Further, by removingthe heat from the surface of the wafer W, it is possible to prepare fora next source gas adsorption process and facilitate a desorption ofby-products from the surface of the wafer W. Also, a gas purge processcan be shortened by facilitating a discharge of gaseous by-productsafter the reaction.

The pressure reduction is performed, under the control of the processcontroller 50, for example, by exhausting the inside of the chamber 1with the use of the gas exhaust unit 7, while fully opening theconductance variable valve 6 a arranged on the gas exhaust line 6between the gas exhaust port 5 and the gas exhaust unit 7. Herein, it ispreferable to decrease the pressure as much as the increase in thepressure increasing process of the step S15. In this way, the pressurecan be controlled to a level required in supplying the source gas for anext cycle.

Next, while the valves 25 b are opened, the purge gas is supplied againfrom the purge gas supply source 27 into the chamber 1 via the gas inletport 17 at a flow rate controlled by the mass flow controller 24 b.Then, the atmosphere inside the chamber 1 is substituted by a lowtemperature purge gas by exhausting the inside of the chamber 1 with thegas exhaust unit 7. Accordingly, the thermal energy conveyed by theenergy transfer gas is removed and, also, reaction by-products existingin the gas phase or absorbed on the surface of the wafer W are removed(step S18). In other words, the heat is removed from the surface of thewafer W by purging the energy transfer gas in the purge process of thestep S18. As a result, it is possible to prepare for a source gasadsorption process of a next cycle. Further, a concentration ofimpurities in the film can be decreased by purging the gaseous reactionby-products.

In the film forming apparatus 100, a high-quality thin filmcorresponding to a monomolecular or a multimolecular adsorption layer ofa film forming material can be formed on the wafer W by performing mainprocesses including the adsorption process for adsorbing the filmforming material on the surface of the wafer W, the purge process forsubstituting the atmosphere inside the chamber with the purge gas andthe reaction process for carrying out the film forming reaction bysupplying the thermal energy to the film forming material on the surfaceof the wafer W through the use of the energy transfer gas. Therefore,thin films can be sequentially deposited on the surface of the wafer Wby repetitively performing the processes of the steps S12 to S18 in FIG.4. The pressure increasing process of the step S15 and the pressuredecreasing process of the step S17 are not prerequisite processes forthe film formation. In other words, it is possible to perform the purgeprocess of the step S14, the reaction process of the step S16 and thepurge process of the step S18 while maintaining the inner pressure ofthe chamber 1 at a constant level.

After a desired film of a predetermined thickness is formed, the wafer Wis unloaded from the loading/unloading port (not shown) by opening thegate valve (not shown) (step S19). In this way, the film forming processfor a single wafer W is completed.

Hereinafter, examples of major processes of the film forming method ofthe present invention will be described with reference to FIGS. 5 to 10.FIG. 5 provides a flowchart showing an example of a film formingreaction performed by introducing into the chamber 1 a reactant gas inaddition to an energy transfer gas during a reaction process. FIG. 6offers a timing chart based on the flowchart of FIG. 5. Although FIG. 6illustrates only a first to a third cycle for convenience, the number ofcycles may be one or more than four depending on desired thin films(same in FIGS. 8, 10 and 14 to 21). Since the details of each processare the same as those described above, the description thereof will beomitted.

First of all, a source gas is adsorbed on a surface of a wafer W in astep S21. At this time, it is preferable that a temperature of the waferW is controlled in advance as described above.

Next, a first purge process is performed to purge a gaseous source gasin a step S22 (gaseous source gas purge process). Then, an innerpressure of the chamber 1 is increased by controlling an exhaustconductance while introducing the purge gas in a pressure increasingprocess of a step S23. Herein, the purge process of the step S22 and thepressure increasing process of the step S23 are overlapped temporally.In a reaction process of a step S24, a film forming reaction is carriedout by simultaneously supplying to the chamber a reactant gas inaddition to an energy transfer gas.

In a step 25, the introduction of the energy transfer gas and thereactant gas is stopped and, also, the inner pressure of the chamber 1is decreased to a level before the pressure increasing process. Then, asecond purge process is performed to purge reaction by-products and theenergy transfer gas having the thermal energy (step S26).

One cycle of the aforementioned steps S21 to S26 is repeated multipletimes as necessary. Herein, the first purge process of the step S22 andthe pressure increasing process of the step S23 can be performedsimultaneously. Further, the pressure decreasing process of the step S25and the second purge process of the step S26 can be performedsimultaneously.

FIG. 7 presents a flowchart describing an example of a film formingreaction performed by introducing into the chamber 1 a reactant gasserving as an energy transfer gas. That is, the heated reactant gas canbe used as the energy transfer gas. FIG. 8 represents a timing chartbased on the flowchart of FIG. 7. Since the details of each process arethe same as those described above, the description thereof will beomitted.

First of all, a source gas is adsorbed on a surface of a wafer W in astep S31. At this time, it is preferable that a temperature of the waferW is controlled in advance as described above.

Next, a first purge process is performed to purge a gaseous source gasin a step S32 (gaseous source gas purge process). Then, an innerpressure of the chamber 1 is increased by controlling an exhaustconductance while introducing the purge gas in a pressure increasingprocess of a step S33. Herein, the purge process of the step S32 and thepressure increasing process of the step S33 are overlapped temporally.In a reaction process of a step S34, a film forming reaction is carriedout by supplying to the chamber an energy transfer gas serving as areactant gas. As for the energy transfer gas serving as the reactantgas, there can be employed, e.g., H₂, NH₃, N₂, N₂H₄, HCOOH, CH₃COOH,CH₃OH, H₂O (vapor), O₃, CO and the like.

In a step 35, the introduction of the energy transfer gas is stoppedand, also, the inner pressure of the chamber 1 is decreased to a levelbefore the pressure increasing process. Then, a second purge process isperformed to purge reaction by-products and the energy transfer gashaving the thermal energy (step S36).

One cycle of the aforementioned steps S31 to S36 is repeated multipletimes as necessary. Herein, the first purge process of the step S32 andthe pressure increasing process of the step S33 can be performedsimultaneously. Further, the pressure decreasing process of the step S35and the second purge process of the step S36 can be performedsimultaneously.

FIG. 9 is a flowchart showing an example of a film forming reactionperformed by introducing only an energy transfer gas into the chamber 1during a reaction process. This is for a case where the film formingreaction is carried out by only supplying the thermal energy by theenergy transfer gas without having to use the reactant gas. FIG. 10illustrates a timing chart based on the flowchart of FIG. 9. Since thedetails of each process are the same as those described above, thedescription thereof will be omitted.

First of all, a source gas is adsorbed on a surface of a wafer W in astep S41. In such a case, it is preferable that a temperature of thewafer W is controlled in advance as described above.

Next, a first purge process is performed to purge a gaseous source gasin a step S42 (gaseous source gas purge process). Then, an innerpressure of the chamber 1 is increased by controlling an exhaustconductance while introducing the purge gas in a pressure increasingprocess of a step S43. Herein, the purge process of the step S42 and thepressure increasing process of the step S43 are overlapped temporally.In a reaction process of a step S44, a film forming reaction is carriedout by supplying only the energy transfer gas into the chamber.

In a step 45, the introduction of the energy transfer gas is stoppedand, also, the inner pressure of the chamber 1 is decreased to apressure level before the pressure increasing process. Then, a secondpurge process is performed to purge reaction by-products and the energytransfer gas having the thermal energy (step S46).

One cycle of the aforementioned steps S41 to S46 is repeated multipletimes as necessary. Herein, the first purge process of the step S42 andthe pressure increasing process of the step S43 can be performedsimultaneously. Further, the pressure decreasing process of the step S45and the second purge process of the step S46 can be performedsimultaneously.

FIGS. 11A to 11J schematically illustrate a principle of a film formingprocess of this embodiment. FIG. 11A shows a wafer W having atemperature controlled to a level at which a source material can beeasily adsorbed. Referring to FIG. 11B, a source material Si is adsorbedby contacting a source gas on a surface of the wafer W having thetemperature controlled to a predetermined level. Next, as shown in FIG.11C, the residual gaseous source material S₁ is removed by performing apurge process with a purge gas P. After an inner pressure of the chamber1 is increased if necessary, a thermal energy E required for a reactionis supplied by injecting a reactant gas S₂ and an energy transfer gas(not shown) heated to a high temperature toward the wafer W having thesource material S₁ adsorbed thereon, as illustrated in FIG. 11D. In thisexample, a chemical reaction takes place between the source material S₁and the reactant gas S₂, thereby forming a first layer of thin film D₁,as shown in FIG. 11E. Herein, the reactant gas S₂ may not be used if notrequired.

After the inner pressure of the chamber 1 is decreased to a level beforethe pressure increasing process if necessary, the energy transfer gashaving the thermal energy or the reaction by-products are removed bycarrying out the purge process with the purge gas P, as illustrated inFIG. 11F. Therefore, in order to deposit a second layer of thin film,the source material S₁ is adsorbed again on the wafer W (on the thinfilm D₁) (FIG. 11G) and, then, the purge process is performed (FIG.11H). After increasing the inner pressure of the chamber 1 if necessary,the reactant gas S₂ and the energy transfer gas are injected (FIG. 11I).As a result, a chemical reaction takes place, forming a second layer ofthin film D₂ (FIG. 11J). Since the subsequent processes are the same asthose for the first layer film forming process, the description thereofwill be omitted. By repetitively performing the aforementionedprocesses, further layers of thin films are sequentially formed on topof the surface of the wafer W until a desired film thickness isachieved. Although FIGS. 11A to 11J depict an example in which the filmis formed by supplying the energy to a monomolecular adsorption layeradsorbed on the wafer W, a thin film can be deposited by supplying theenergy to a multimolecular adsorption layer.

FIG. 12 is a cross sectional view illustrating a schematic configurationof a film forming apparatus 101 in accordance with a second embodimentof the present invention. The film forming apparatus 101 is differentfrom the film forming apparatus 100 of the first embodiment in that agas exhaust port 5 is formed on a bottom wall 1 a of a chamber 1 andconnected with a gas exhaust unit 7 via a gas exhaust line 6 connectedtherewith, the gas exhaust unit 7 having a high speed vacuum pump. It ispreferable that the gas exhaust port 5 and the gas inlet port 17 arelocated at diametrically opposite locations with respect to the mountingtable 3. A conductance variable valve 6 a serving as a pressure controlunit is arranged on the gas exhaust line 6 between the gas exhaust port5 and the gas exhaust unit 7. By exhausting a gas inside the chamber 1with an operation of the gas exhaust unit 7, an inner pressure of thechamber 1 can be decreased to a predetermined vacuum level at a highspeed via the gas exhaust line 6 while controlling the pressure.Although the gas exhaust port 5 is disposed as shown in FIG. 12, a flowof the source gas can be formed from the gas inlet port 17 toward thegas exhaust port 5 in a direction parallel to the surface of the wafer Wmounted on the mounting table 3, as indicated by white arrows of FIG.12. Consequently, the film forming source material can be effectivelyadsorbed on the surface of the wafer W. Since other configurations ofthe film forming apparatus 101 in accordance with the second embodimentare the same as those of the film forming apparatus of the firstembodiment, like reference numbers are given to like parts and thedescription thereof will be omitted.

FIG. 13 provides a cross sectional view showing a schematicconfiguration of a film forming apparatus 102 in accordance with a thirdembodiment of the present invention. Unlike the film forming apparatus100 of the first embodiment or the film forming apparatus 101 of thesecond embodiment, the film forming apparatus 102 employs a structure inwhich a source gas, a purge gas, a reactant gas and an energy transfergas are all supplied via a shower head.

To be specific, a shower head 60 is provided on a ceiling wall 1 c ofthe chamber 1 and includes an upper block body 61, an intermediate blockbody 62 and a lower block body 63. Alternately formed in the lower blockbody 63 are gas injection openings 64 and 65 for discharging gases. Afirst and a second gas inlet port 66 and 67 are formed on a top surfaceof the upper block body 61. The first gas inlet port 66 is connectedwith an energy transfer gas supply source 23 a and a reactant gas supplysource 23 b via a bifurcated gas line 72. The second gas inlet port 67is connected with a film forming source gas supply source 26 and a purgegas supply source 27 via a bifurcated gas line 73. Moreover, the heatedreactant gas can be used as the energy transfer gas. In such a case, theenergy transfer gas supply source 23 a does not need to be provided inaddition to the reactant gas supply source 23 b.

A plurality of gas channels 68 are branched from the first gas inletport 66 inside the upper block body 61. Further, gas channels 69 areformed in the intermediate block body 62 and the gas channels 68communicate with the gas channels 69. Furthermore, the gas channels 69communicate with the gas injection openings 64 of the lower block body63.

Moreover, a plurality of gas channels 70 are branched from the secondgas inlet port 67 inside the upper block body 61. In addition, gaschannels 71 are formed in the intermediate block body 62 and the gaschannels 70 communicate with the gas channels 71. The gas channels 71communicate with the gas injection openings 65 of the lower block body63.

Provided around the gas injection openings 64 are heaters 74 serving asheating units for heating the energy transfer gas and the reactant gasinside the shower head 60. Further, insulating units 75 are providedaround the heaters 74 to insulate the heaters 74, the insulating units75 being made of a material having a low thermal conductivity, e.g.,heat resistant synthetic resin, quartz, ceramic or the like.

Gas exhaust ports 76 a and 76 b are formed on a bottom wall 1 a of thechamber 1, e.g., at diametrically opposite locations with respect to themounting table 3 and connected with a gas exhaust unit 7 having a highspeed vacuum pump via gas exhaust lines 77 a and 77 b connectedtherewith. By exhausting a gas inside the chamber 1 with an operation ofthe gas exhaust unit 7, an inner pressure of the chamber 1 can bedecreased to a predetermined vacuum level at a high speed via the gasexhaust lines 77 a and 77 b. Moreover, the pressure can be controlled tobe increased or decreased by adjusting an exhaust conductance with theconductance variable valves 77 c and 77 d arranged on the gas exhaustlines 77 a and 77 b between the gas exhaust ports 76 a and 76 b and thegas exhaust unit 7 under the control of the process controller 50. Atthis time, the gas exhaust unit 7 and the conductance variable valves 77c and 77 d cooperatively serve as a pressure control unit.

By connecting the gas line 73 with the shower head 60 as shown in FIG.13, the source gas from the film forming source gas supply source 26 isdischarged through the gas injection openings 65 of the lower block body63 facing the wafer W via the second gas inlet port 67 and the gaschannels 70 and 71. Accordingly, the source gas can collide against thesurface of the wafer W in a substantially vertical direction. Further,by exhausting the gas in the chamber 1 through the gas exhaust ports 76a and 76 b formed on the bottom wall 1 a of the chamber 1, the sourcegas that has collided against the surface of the wafer W can flow towardthe gas exhaust ports 76 a and 76 b in a direction substantiallyparallel to the surface of the wafer W mounted on the mounting table 3.Consequently, the film forming material can be effectively adsorbed onthe surface of the wafer W.

By connecting the gas line 72 with the shower head 60, the energytransfer gas from the energy transfer gas supply source 23 a and thereactant gas from the reactant gas supply source 23 b are discharged, ifnecessary, through the gas injection openings 64 of the lower block body63 facing the wafer W via the first gas inlet port 66 and the gaschannels 68 and 69. Accordingly, the energy transfer gas and thereactant gas collide against the surface of the wafer W in asubstantially vertical direction. As a result, the thermal energy can beeffectively supplied to the surface of the wafer W where the reactiontakes place.

Since other configurations of the film forming apparatus 102 of thethird embodiment are the same as those of the film forming apparatus 100of the first embodiment, like reference numbers are given to like partsand, further, the description thereof will be omitted.

Hereinafter, the present invention will be described in detail based onexamples. However, the present invention is not limited to followingexamples.

Example 1

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C.

A liquid source material of Ru(EtCp)₂ was introduced into a vaporizerheated to 150° C. and, then, the vaporized gas was introduced into thevacuum film forming apparatus by a carrier gas of Ar. As for anoxidizing gas (reactant gas), O₂ was used. Introduced into the chamber 1were Ru(EtCp)₂, Ar serving as a carrier and dilution gas; and O₂ servingas a reactant gas and Ar serving as an energy transfer gas heated to ahigh temperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 14 shows a timing chart of the film forming processin this example:

Step 1;

Ru(EtCp)₂ of 0.1 g/min and the carrier gas of Ar of 100 mL/min (sccm)were set to flow for 20 seconds while setting an inner pressure of thechamber at 400 Pa (3 Torr),

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing,

Step 3;

Ar and O₂, each being heated to 500° C., were set to flow for 10 secondswhile setting the inner pressure of the chamber at 1333 Pa (10 Torr).Each of the flow rates of Ar and O₂ was 500 mL/min (sccm)

Step 4;

A purge process was performed by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 ten times, a Ru film having a filmthickness of 30 nm was formed.

Example 2

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C.

A liquid source material of Ru(EtCp)₂ was introduced into a vaporizerheated to 150° C. and, then, the vaporized gas was introduced into thevacuum film forming apparatus by a carrier gas of Ar. Introduced intothe chamber 1 were Ru(EtCp)₂, Ar serving as a carrier and dilution gas;and H₂ serving as a reactant gas and Ar as an energy transfer gas heatedto a high temperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 15 shows a timing chart of the film forming processin this example:

Step 1;

Ru(EtCp)₂ of 0.2 g/min and the carrier gas of Ar of 100 mL/min (sccm)were set to flow for 20 seconds while setting an inner pressure of thechamber at 400 Pa (3 Torr).

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing,

Step 3;

Ar and H₂, each being heated to 500° C., were set to flow for 10 secondswhile setting the inner pressure of the chamber at 1333 Pa (10 Torr).Each of the flow rates of Ar and H₂ was 500 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 eight times, a Ru film having a filmthickness of 27 nm was formed.

Example 3

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C.

A liquid source material of Ru(EtCp)₂ was introduced into a vaporizerheated to 150° C. and, then, the vaporized gas was introduced into thevacuum film forming apparatus by a carrier gas of Ar. Introduced intothe chamber 1 were Ru(EtCp)₂, Ar serving as a carrier and dilution gas;and Ar serving as an energy transfer gas heated to a high temperaturefor a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 16 shows a timing chart of the film forming processin this example:

Step 1;

Ru(EtCp)₂ of 0.2 g/min and the carrier gas of Ar of 100 mL/min (sccm)were set to flow for 20 seconds while setting an inner pressure of thechamber at 400 Pa (3 Torr).

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing.

Step 3;

Ar heated to 500° C. was set to flow for 10 seconds while setting theinner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Arwas 1000 mL/min (sccm).

Step 4;

A purge process was performed by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 eight times a Ru film having a filmthickness of 29 nm was formed.

Example 4

A wafer W having a diameter of 300 mm is loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C.

A liquid source material of Ru(EtCp)₂ was introduced into a vaporizerheated to 150° C. and, then, the vaporized gas was introduced into thevacuum film forming apparatus by a carrier gas of Ar. Introduced intothe chamber 1 were Ru(EtCp)₂, Ar serving as a carrier gas and dilutiongas; and Ar serving as an energy transfer gas heated to a hightemperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 5:

Step 1;

Ru(EtCp)₂ of 0.5 g/min and the carrier gas of Ar of 100 mL/min (sccm)were set to flow for 20 seconds while setting an inner pressure of thechamber at 400 Pa (3 Torr),

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing,

Step 3;

Ar heated to 500° C. was set to flow for 10 seconds while setting theinner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Arwas 1000 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr),

Step 5;

Ru(EtCp)₂ of 0.5 g/min and the carrier gas of Ar of 100 mL/min (sccm)were set to flow for 20 seconds while setting the inner pressure of thechamber at 666.6 Pa (5 Torr).

By performing four times the steps 1 to 5 as a nucleation process andsix times the steps 5, 2, 3 and 4 as a main deposition process, a Rufilm having a film thickness of 32 nm was formed.

Example 5

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 10° C.

A solid source material of Ru₃(CO)₁₂ in a vessel having a temperaturecontrolled to 50° C. was introduced into the vacuum film formingapparatus by using a bubbling method employing Ar as a carrier gas.

Introduced into the chamber were Ru₃(CO)₁₂, Ar serving as a carrier anddilution gas; and Ar serving as an energy transfer gas heated to a hightemperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 17 shows a timing chart of the film forming processin this example:

Step 1;

Ru₃(CO)₁₂ of 1 mL/min (sccm) and the carrier gas of Ar of 100 mL/min(sccm) were set to flow for 20 seconds while setting an inner pressureof the chamber at 400 Pa (3 Torr).

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing,

Step 3;

Ar heated to 500° C. was set to flow for 10 seconds while setting thepressure inside the chamber at 1333 Pa (10 Torr). The flow rate of Arwas 1000 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 fifty times, a Ru film having a filmthickness of 5 nm was formed.

Example 6

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C.

A source material of Ta(Nt-Am) (NMe₂)₃ (=TAIMATA) was introduced into avaporizer heated to 120° C. via a line heated to 50° C. and, then, thevaporized gas was introduced into the vacuum film forming apparatus by acarrier gas of Ar. Introduced into the chamber 1 were Ta(Nt-Am) (NMe₂)₃,Ar serving as a carrier and dilution gas; and NH₃ serving as a reactantgas and Ar serving as an energy transfer gas heated to a hightemperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 18 shows a timing chart of the film forming processin this example:

Step 1;

Ta(Nt-Am) (NMe₂)₃ of 0.2 g/min (sccm) and the carrier gas of Ar of 100mL/min (sccm) were set to flow for 20 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr)

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing.

Step 3;

NH₃ and Ar, each being heated to 500° C., were set to flow for 10seconds at while setting the inner pressure of the chamber at 1333 Pa(10 Torr). The flow rates of NH₃ and Ar were 700 and 300 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 eight times, a TaN film having a filmthickness of 54 nm was formed.

Example 7

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C. A source of Ta(Nt-Am) (NMe₂)₃ was introducedinto a vaporizer heated to 120° C. via a line heated to 50° C. and,then, the vaporized gas was introduced into the vacuum film formingapparatus by a carrier gas of Ar. Introduced into the chamber 1 wereTa(Nt-Am) (NMe₂)₃, Ar serving as a carrier and dilution gas; and Arserving as an energy transfer gas heated to a high temperature for afilm forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 19 shows a timing chart of the film forming processin this example:

Step 1;

Ta(Nt-Am) (NMe₂)₃ of 0.2 g/min (sccm) and the carrier gas of Ar of 100mL/min (sccm) were set to flow for 20 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr).

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing.

Step 3;

Ar heated to 500° C. was set to flow for 10 seconds while setting theinner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Arwas 1000 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 ten times, a TaN film having a filmthickness of 25 nm was formed.

Example 8

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 100° C.

A source material of Ta(Nt-Am) (NMe₂)₃ was introduced into a vaporizerheated to 120° C. via a line heated to 50° C. and, then, the vaporizedgas was introduced into the vacuum film forming apparatus by a carriergas of Ar. Introduced into the chamber 1 were Ta(Nt-Am)(NMe₂)₃, Arserving as a carrier and dilution gas; and Ar serving as an energytransfer gas heated to a high temperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4:

Step 1;

Ta(Nt-Am) (NMe₂)₃ of 0.2 g/min (sccm) and the carrier gas of Ar of 100mL/min (sccm) set to flow for 20 seconds while setting an inner pressureof the chamber at 400 Pa (3 Torr).

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing.

Step 3;

Ar heated to 500° C. was set to flow for 10 seconds while setting theinner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Arwas 1000 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 ten times, a TaN film having a filmthickness of 25 nm was formed.

Example 9

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 10° C.

A solid source material of W(CO)₆ in a vessel having a temperaturecontrolled to 50° C. was introduced into the vacuum film formingapparatus by using a bubbling method employing Ar as a carrier gas.Introduced into the chamber were W(CO)₆, Ar serving as a carrier anddilution gas; and Ar serving as an energy transfer gas heated to a hightemperature for a film forming reaction.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 20 provides a timing chart of the film formingprocess in this example:

Step 1;

W(CO)₆ of 5 mL/min (sccm) and the carrier gas of Ar of 100 mL/min (sccm)were set to flow for 20 seconds while setting an inner pressure of thechamber at 400 Pa (3 Torr).

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing.

Step 3;

Ar heated to 500° C. was set to flow for 10 seconds while setting theinner pressure of the chamber at 1333 Pa (10 Torr). The flow rate of Arwas 1000 mL/min (sccm).

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 twenty times, a W film having a filmthickness of 10 nm was formed.

Example 10

A wafer W having a diameter of 300 mm was loaded via a transfer robot(not shown) into an aluminum vacuum film forming apparatus having amounting table whose temperature is controllable as in FIG. 1 and thenmounted on the mounting table having a temperature controlled to apreset level of 10° C.

A solid source material of W(CO)₆ in a vessel having a temperaturecontrolled to 50° C. was introduced into the vacuum film formingapparatus by using a bubbling method employing Ar as a carrier gas.Introduced into the chamber were W(CO)₆, Ar serving as a carrier anddilution gas; and H₂ serving as a reactant gas heated to a hightemperature for a film forming reaction and Ar as an energy transfergas.

Next, a film forming process was carried out by performing followingsteps 1 to 4. FIG. 21 provides a timing chart of the film formingprocess in this example:

Step 1;

W (CO)₆ of 5 mL/min (sccm) and the carrier gas of Ar of 100 mL/min(sccm) were set to flow for 20 seconds while setting an inner pressureof the chamber at 400 Pa (3 Torr),

Step 2;

A purge process was performed by flowing a dilution gas of Ar of 500mL/min (sccm) as a purge gas for 10 seconds while setting an innerpressure of the chamber at 400 Pa (3 Torr) and, then, the inner pressureof the chamber was increased to 1333 Pa (10 Torr) while the purge gaswas flowing,

Step 3;

H₂ and Ar, each being heated to 500° C., were set to flow for 10 secondswhile setting the inner pressure of the chamber at 1333 Pa (10 Torr).The flow rates of H₂ and Ar were 800 and 200 mL/min (sccm),respectively.

Step 4;

A purge process was carried out by flowing a dilution gas of Ar of 1000mL/min (sccm) as a purge gas for 10 seconds while setting the innerpressure of the chamber at 400 Pa (3 Torr).

By repeating the steps 1 to 4 twenty times, a W film having a filmthickness of 10 nm was formed.

The present invention may be variously modified without being limited tothe aforementioned embodiments.

For example, although the heaters 15 for heating the energy transfer gasare provided around the gas injection openings 11 of the shower head 10in the film forming apparatus 100 of FIG. 1, the heaters may beinstalled in the diffusion space 14 of the shower head 10. In such acase, there can be used a cylindrical heater 210 having a bar-shapedresistance 212 installed in an elongated cylindrical container 211 madeof an insulating material such as heat resistant synthetic resin,quartz, ceramic or the like, as shown in FIGS. 22 and 23. The bar-shapedresistance 212 is connected with a heater power supply (not shown) vialead lines 215, so that an inside of the container 211 can be rapidlyheated by supplying power to the heater 210. Further, a gas inlet 213 isprovided at one place of an upper portion of the container 211. Aplurality of gas outlets 214 communicating with the gas injectionopenings 11 of the shower head 10 are formed at a lower portion of thecontainer 211. The energy transfer gas can be rapidly heated whilepassing through the inside of the container 211. Moreover, a number ofthe cylindrical heaters 210 may be disposed side by side inside thediffusion space 14 of the shower head 10.

Although the first to the third embodiments employ the fixed mountingtable 3, there may be used a mounting table 3 horizontally rotatable bya rotating unit. In such a case, a more uniform thickness and quality ofa thin film formed on the surface of the wafer W can be achieved duringthe adsorption process for adsorbing a film forming material on thesurface of the wafer W and the reaction process for carrying out a filmforming reaction on the surface of the wafer W.

The present invention can be appropriately used for forming a desiredfilm on a substrate such as a semiconductor wafer or the like during amanufacturing process of various semiconductor devices, for example.

1. A film forming apparatus comprising: a processing chamber,accommodating therein a substrate, for performing a film formingprocess; a mounting table for mounting thereon the substrate in theprocessing chamber; a source gas inlet for introducing a source gas intothe processing chamber; an energy transfer gas inlet, which includes aplurality of gas injection openings, for injecting an energy transfergas through the gas injection openings toward a surface of the substratemounted on the mounting table in the processing chamber; a gas exhaustunit for vacuum exhausting an inside of the processing chamber and; aheater unit for heating the energy transfer gas, wherein the heater unitis disposed in the energy transfer gas inlet such that the energytransfer gas is heated by the heater unit before being injected from thegas injections openings into the inside of the processing chamber. 2.The film forming apparatus of claim 1, wherein the heater unit includescylindrical ceramic members and resistances embedded in a coil shape inthe ceramic member, each of the gas injection openings being surroundedby one of the cylindrical ceramic members.
 3. The film forming apparatusof claim 2, wherein insulation members are provided around thecylindrical ceramic members to thermally insulate the heater unit. 4.The film forming apparatus of claim 3, wherein the insulation membersare made of a material selected from the group consisting of heatresistant synthetic resin, quartz and ceramic.
 5. The film formingapparatus of claim 1, wherein the energy transfer gas inlet includes ashower head disposed in an upper portion of the processing chamber andhaving the gas injection openings and a diffusion space disposedthereabove and the heater unit installed in the diffusion space.
 6. Thefilm forming apparatus of claim 1, wherein the heater unit includescylindrical heaters, each of which has an elongated cylindricalcontainer made of an insulation material and a bar-shaped resistanceinstalled in the elongated cylindrical container.
 7. The film formingapparatus of claim 6, wherein the cylindrical container is provided witha gas inlet for introducing the energy transfer gas there into aplurality of gas outlets communicating with the gas injection openings,and the energy transfer gas is heated while passing through an inside ofthe cylindrical container.
 8. The film forming apparatus of claim 7,wherein the cylindrical heaters are disposed side by side.
 9. The filmforming apparatus of claim 1, wherein power is supplied from a heaterpower supply to the heater unit via a lead line.
 10. The film formingapparatus of claim 6, wherein the bar-shape resistance is connected witha heater power supply via lead lines, thereby rapidly heating the energytransfer gas at an inside of the cylindrical container by supplyingelectrical power to the heater unit.
 11. A film forming apparatuscomprising: a processing chamber, accommodating therein a substrate, forperforming a film forming process; a mounting table for mounting thereonthe substrate in the processing chamber; a source gas inlet forintroducing a source gas into the processing chamber; an energy transfergas inlet, which includes a plurality of gas injection openings, forinjecting an energy transfer gas through the gas injection openingstoward a surface of the substrate mounted on the mounting table in theprocessing chamber; a gas exhaust unit for vacuum exhausting an insideof the processing chamber; a heater unit for heating the energy transfergas; and a power supply connected to the heater unit to supply anelectric power thereto, wherein the heater unit is disposed inside theenergy transfer gas inlet so that the energy transfer gas is heated bybeing introduced into the energy transfer gas inlet.
 12. The filmforming apparatus of claim 11, wherein the heater unit includescylindrical ceramic members and resistances embedded in a coil shape inthe ceramic member, each of the gas injection openings being surroundedby one of the cylindrical ceramics members.
 13. The films formingapparatus of claim 12, wherein insulation members are provided aroundthe cylindrical ceramic members to thermally insulate the heater unit.14. The film forming apparatus of claim 13, wherein the insulationmembers are made of a material selected from the group consisting ofheat resistant synthetic resin, quartz and ceramic.
 15. The film formingapparatus of claim 11, wherein the energy transfer gas inlet includes ashower head disposed in an upper portion of the processing chamber andhaving the gas injection openings and a diffusion space disposedthereabove and the heater unit installed in the diffusion space.
 16. Thefilm forming apparatus of claim 11, wherein the heater unit includescylindrical heaters, each of which has an elongated cylindricalcontainer made of an insulation material and a bas-shaped resistanceinstalled in the elongated cylindrical container.
 17. The film formingapparatus of claim 16, wherein the cylindrical container is providedwith a gas inlet for introducing the energy transfer gas thereinto aplurality of gas outlets communicating with the gas injection openings,and the energy transfer gas is heated while passing through an inside ofthe cylindrical container.
 18. The film forming apparatus of claim 17,wherein the cylindrical heaters are disposed side by side.
 19. The filmforming apparatus of claim 16, wherein the bar-shape resistance isconnected with the power supply via lead lines, thereby rapidly heatingthe energy transfer gas at an inside of the cylindrical container bysupplying electrical power to the heater unit.